The present invention relates to an information processing system and an access method, and in particular, to detection of a failure.
Recently, the data amount treated by an information processing system has been significantly increased. A storage device of a large capacity should assure an I/O performance and reliability to match the storage capacity. For this, there has been developed one for multiplexing the logical path (I/O path) to the storage device and allocating to the logical path the data input/output request (I/O request) to the storage device.
As such a technique, there is one for improving the reliability of the system including a computer and a storage device connected by a plurality of paths by selecting a path having less possibility of failure after calculating the possibility of the failure for each path from the number of I/O requests to the path. (For example, U.S. Pat. No. 6,802,021.)
It is possible to improve the reliability by using a configuration for selecting one of the paths according to generation of a failure or the possibility of generation of a failure.
However, when an I/O request is assigned to a path excluding the path where failure has occurred or an I/O request is assigned to a path having a low possibility of generation of a failure so as to improve the reliability, the I/O requests are concentrated to the path, which in turn lowers the throughput.
In a system having a configuration including an information processing device such as a computer and a storage device which are connected by a plenty of paths, various methods are used as a method for storing data in the storage device. For example, data mirroring is performed for dually storing data when the data is very important. Furthermore, when performing the mirroring, there are methods for controlling the mirroring by the storage device or by the information processing device.